Continuous annealing apparatus



Filed Nov. 17, 1924 3 Sheets-Sheet gwve'nfou J 5: j 3 1 I I RN RM July16, 1929.

H. M. NAUGLE ET AL l.72l,350

CONTINUOUS ANNEALING APPARATUS Filed Nov. 17, 1924 3 Sheets-Sheet 3Patented July 16, 1929.

' UNITED STATES PATENT OFFICE.

HARRY M. NA'UGLE AND ARTHUR J. TOWNSEND, OF CANTON, OHIO, ASSIONOBB, B!

MESNE ASSIGNMENTS, TO THE AMERICAN ROLLING MILL COMPANY, 01 MIDDLE-TOWN, OHIO, A CORPORATION OF OHIO.

OONTINUOUS ANNEALING APPARATUS.

The invention relates to apparatus which may be used for carrying outthecontmuous quick annealing of a strip sheet of metal, referred to inour application for method 5 of making strip' sheets, filed August 22,

1922, Serial No. 583,612, matured in patent No. 1.536. 28. dated April28, 1925, and

reissued June '14, 1927, Reissue No. 16,652;

and for carrying out the continuous annealing processes set forth in ourapplication for patent tiled April 4, 1924, Serial No.

704.157: and the object of the improvement is to anneal the metal in amanner that will give the product the uniform ductile and otherstructural characteristics which are necessary for deep drawing andforming or stan'iping operations.

A readjustment of the grains of metal to relieve them of the strainsproduced by a rolling operation. and more particularly by a rapid coldrolling reduction, cannot be accomplished by the ordinary box annealingof a mass or coil of material, for the reason that the longer period oftime required for properly heating the inner portions of the mass orcoil, not only results in the overannealing of the outer' portionthereof. but in the production of a grain growth in a considerableportion of the mass or coil. which destroys the ductility anduniformity, and also decreases the strength of the material in the outerportion of the mass or coil.

The present improvement is particularly concerned with the annealing ofsteel having a carbon content of less than .20% for the reason that sucha low carbon steel is best suited for deep drawing and forming orstamping operations; and for properly annealing the same, the metal mustbe uniformly heated to a temperature of from ]300 to 1600 F. As a graingrowth, sometimes known as Steads brittleness, may occur at atemperature less than 1400 uniformly heated F.. if the same ismaintained long enough;

and gradually without, however, quenching the same to harden itsstructure.

This general object of the improvement may be attained by annealing thestrip b the direct action of electric resistors whi 6 movingcontinuously through a heating chamber, in which the resistors aretransversely located adjacent to and parallel w th the strip, by whichthe same ma be and the degree of cat defimtely controlled at all pointsin the heatmg furnace; and then to promptly cool the strip by moving itcontinuously through a tubular duct surrounded by a moving body or wateror other heat absorbing liquid, b whlch the strip may be quickly andgradua ly reduced to a non-oxidizingtemperature when exposed to the air.

Other objects of the improvement relate to the combination in series ofstrip levelng, spot welding and solution washer means in front of theheating and cooling apparatus, and of conveyer rolls, strip shearing andstrip coiling apparatus in rear of the same; for continuously carryingon the annealing process upon a series of successive strips. withoutstopping the movement of the strip which is passing through the heatingand cooling apparatus.

The improved apparatus is illustrated, more or less conventionally, inthe accompanying drawings forming part hereof, in which Figure 1 is aside elevation, showing some parts in section, of the entire series ofcombined apparatus;

Fig. 2, an enlarged side elevation, mostly in longitudinal section,showing interior de tails of the heating and cooling chambers; gig. 3, across section on line 3-3, Fig. 2; an

Fig. 4 a cross section on lines-4, Fig. 2.

Similar numerals refer to similar. parts throughout the drawings.

The apparatus may include a coil box A, a. strip leveler B, a, travelingspot welder C, a solution washer D, an entering seal E, an electricheating furnace F, awater cooling duct- G. an exit sea-l H, conveyerrolls I, a double and shear J and a stri coiler K arranged in series asshown in Fig. 1.

The coil box A may be of any ordinary construction for holding a coil 10of a strip other apparatus used in as the entering seal 11 of steel orthe like, and permit-ting the same to unwind for a continuous annealing;and the strip leveler B may include two sets of rolls 12 of any wellknown construction and operation for flattening the sheet and removinguneven fullness or buckles which may have been caused by reducing rollsor producing the strip; The spot welder C may include a set ofelectrodes 13 mounted in a frame 14 supported on a carriage 14',provided with wheels 15 riding on a track 16, together with grippingdevices 14 on the front and rear side of the frame, for clamping andholding successive strips with their ends overlapped, in positionbetween the electrodes for a spot welding operation while the carriageis traveling forward on the track.

The solution washer D may include supporting rolls 17 and transversetubes 18 suit- -ably apertured for spraying a hot soda solution upon thestrip to remove grease and rit therefrom, and like tubes 18 may also E8provided for air drying the strip in rear of the cleaner.

The entering seal E may be of the liquid type provided with guide rolls19, 19 and 19" as described in detail in said application Serial No.704,15 I

The heating furnace F may include a cylindric steel shell 20 mounted onsupports 21, lined with-a thick body of heat insu lating material 22,within which is provided a lining of fire brick 23 or other refractorymaterial, forming a support for transverse electric resistors 24 and 24'parallel-1y positioned above and below and forming between them alongitudinal heating chamber 25, in which are provided a series oftransverse skids 26 for supporting a strip 11 as it is moved endwisethrough the chamber from the entering seal E at its port and to thecooling duct G at its rear end.

By these means, the strip may be heated directly by the action of theelectric resistors, in a uniform manner from end to end of the furnace;and the degree and continuity of heat can be readily controlled at allpoints in the heatin duct.

The cooling duct may be a series of end connected iron tubes 27 and 27extending rearward from the rear end of the furnace, and the sections ofthe same may be surrounded by tanks or troughs 28 containing water forcooling the conduit and the strip moving through the same.

The cooling troughs may be provided with a water inlet pipe 29, a waterconnecting pipe 29 and an over-flow pipe 29 so as to cause a continuousflow of cooling water from the forward toward the rear end of eachtrough.

The exit seal H may be of the same type E, and may'likewise be providedwith reversely arranged rolls 19,

19' and 19 for guiding the strip through the seal. Each sealing box isprovided with an inlet pipe for supplying the same with sealing water orother liquid 30.

The conveyer rolls I may include two stands of pinch rolls 31 arrangedfor drawing a strip through the apparatus and conveying it rearward tothe double end shear J, and between these rolls may be providedtransverse pipes 31 suitably apertured for hot air drying the strips.

The shear J is provided with a shearing die 32 on its front and rearsides, and a shearing punch 33 operating between them, for shearing thejoint of two strips in front and in rear of their overlapped ends, so asto neatly disconnect them after the annealing process is completed.

The strip coiler K may be of any well known construction for winding theannealed strip 11' into a coil 10, and it is prefcrably provided with anindependentmotor 34 for this purpose.

During the operation of the apparatus the heating and cooling chambersare completely filled, to the exclusion of air, with a neutral or areducing gas, for preventing an oxidation of the surface of the strip orto remove any oxidation there may be thereon; and this gas may beintroduced through a pressure inlet pipe 35 into one of the water sealedboxes 36, each one of which is preferably provided with an outletpressure valve to permit a renewal of the gas in the duct.

In the operation of the apparatus, a strip sheet, which has beenflattened by the leveler B, joined to another strip by the spot welderand acted upon by the spray cleaner D, is moved continuously endwisethrough the heating chamber 25, and cooling duct G, wherein itis heatedrapidly and uniformly by the electric resistors to an annealingtemperature, which temperature is maintained and continued only for thebrief period necessary for a proper annealingof the metal, which may notexceed one minute, whereupon it is prompty cooled gradually by the heatabsorbing water surrounding the tubular duct.

In this manner a continuous uick annealing is accomplished, and the riefperiod during which the annealing temperature is maintained andcontinued, prevents the production of an objectionable grain growth orSteads brittleness, so that the annealed strip thus produced ischaracterized by a uniformly fine grained. structure and a highlyductile quality, which adapts it for deep drawing operations.

By the improved apparatus strip sheets of different gauges and of morethan ordina widths can be continuously annealed without developing anyobjectionable grain growth. In actual practice any given ortion of astrip sheet, one-sixteenth 0 an inch in thickness may be heated toatemperature of 1600, maintained at that temperaturefor about one minute,and then cooled to a nonoxidizin temperature, all within a period ofabout t ree minutes. This operation can be carried on continuously withrespect to all portions of each strip, and of successive vstrips whichhave been joined together, without stopping the movement of the stripwhich is passing through the heating chamber and cooling duct.

We claim 1. Apparatus for annealing steel stri s and the like, includingstrip flattening rol s, a heating chamber, a cooling duct, all arrangedin series for flattening and continuously annealing a'moving' strip, andmeans for continuously movin the strip through the apparatus for controling the degree and continuity of annealing throughout the strip.

2. Apparatus for annealing steel strips and the like, including atravelling spot Welder, a heating chamber, a cooling duct, all arrangedin series for connecting the ends of successive moving strips andcontinuously annealing the same, and means for continuously moving thestrip through the apparatus for controlling the degree and continuity ofannealing throughout the strip;

3. Apparatus for. annealing steel strips and the like, including atravelling spot welder, a heating chamber, a cooling duct, a

double end shear, all arranged in series for connecting, continuouslyannealing and disconnecting successive moving strips, and

paratus for controlling the degree and eontinuity of cleaning andannealing throughout the strip.

5. Apparatus for annealing steel strips and the like, including aheating chamber with transverse electric resistors opposing each otherin parallel relation, and a coolingduct extending endwise from theheating chamber surrounded by heat absorbing liquid, there being intakeand exit openings for a stri at the remote ends of the cham ber and uct,liquid seals for the openings, means for filling the chamber and ductwith a reducin gas, and means for continuously drawin t e strip throughthe apparatus for control ing the degree and continuity of annealingthroughout the stri In testimony that we claim the above, we havehereunto subscribed our names.

HARRY M. NAUGLE. ARTHUR J. TOWNSEND.

